Biological filler for enhancing denitrification of aerobic tank as well as preparation and application of biological filler

Abstract

The invention discloses a biological filler for enhancing denitrification of an aerobic tank as well as preparation and application of the biological filler, the problem of weak activity of denitrifying bacteria is successfully solved by loading three layers of biological fillers, namely an inner layer-denitrifying bacteria, a middle layer-conducting layer and an outer layer-nitrifying bacteria, on the filler, and rapid formation of a biological membrane is realized. In addition, a metal conducting layer is additionally arranged in the middle to participate in electron transfer in the microbial denitrification process, and the biological membrane layers on the two sides achieve rapid formation of biological membranes so as to achieve conversion and removal of nitrogen. According to the method, the biological activity of the thalli can be kept, the rapid formation of a biological membrane is realized, and the separation of the thalli and refractory organic matters can be promoted, so that the toxic action on the thalli is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of water treatment, and in particular relates to a biological filler for denitrification enhancement in an aerobic pool and a preparation method and application thereof. Background Art

[0002] Nitrogen is an element widely present in nature and one of the common pollutants in water bodies. Due to the use of pesticides and fertilizers and various daily human activities, a large amount of nitrogen-containing substances flow into water environments such as rivers, lakes, etc., causing nitrogen pollution in the water environment. At the same time, nitrogen pollution in water bodies will bring many adverse consequences. Excessive nitrogen will cause eutrophication, lead to hypoxia in water bodies, affect the survival of underwater organisms, and even cause "dead zones", causing serious damage to aquatic ecosystems. In addition, ammonia nitrogen and nitrite nitrogen will directly affect the sensory properties and transparency of water bodies. High concentrations of ammonia nitrogen will reduce the pH value of water bodies and cause toxic effects on fish and other aquatic organisms. At the same time, if untreated or improperly treated nitrogen-containing wastewater is directly discharged into drinking water sources, the nitrites and nitrates in it will pose a threat to human health. Long-term intake of high concentrations of nitrates will increase the risk of blue baby syndrome in infants.

[0003] Therefore, efficient denitrification and stable compliance have always been the focus of wastewater treatment plants. When the influent of municipal sewage treatment plants is domestic sewage, the B / C and C / N ratios are sufficient, and the denitrification effect of the biochemical stage is significant; however, municipal sewage treatment plants not only treat domestic sewage, but also often accept a large amount of industrial wastewater. Although it meets the discharge standards after pretreatment and then enters the sewage treatment plant, the residual organic pollutants in the discharged water are mostly difficult to degrade or even toxic, such as polycyclic aromatic hydrocarbons and heterocyclic compounds, which have poor water solubility and stable ring structures. They are not only difficult to be used by microorganisms, but also inhibit the growth of microorganisms, which poses a severe challenge to traditional biological denitrification processes. Studies have shown that phenolic compounds have a serious inhibitory effect on both nitrifying and denitrifying bacteria, and the inhibitory effect is significantly enhanced with the increase of substituents. Therefore, how to enhance the activity of denitrifying bacteria and achieve efficient deep denitrification in the treatment of municipal sewage containing industrial wastewater has become a new challenge. Summary of the invention

[0004] Biological denitrification technology has been widely studied and applied due to its high denitrification capacity and low operating cost. Among them, the moving bed biofilm reactor (MBBR) process has attracted much attention due to its advantages such as high organic load, small footprint, low energy consumption, and enhanced denitrification and phosphorus removal. It can solve the problem of excessive ammonia nitrogen in low temperature in winter to a certain extent, and is particularly suitable for the upgrading and transformation of sewage treatment plants. Among them, the filler, as the core of the process, has the function of slow-release nutrition and biofilm carrier. Studies have shown that the physical properties, specific surface area, porosity, etc. of the filler are key factors affecting the efficiency of sewage treatment. Therefore, it is necessary to study, select and upgrade the existing common fillers. In addition, some anaerobic bacteria can complete the detoxification and ring opening of phenolic substances under anaerobic conditions. To this end, the use of bioaugmentation means to selectively enrich such microorganisms in the denitrification system and complete colonization can effectively alleviate the toxic inhibition of refractory organic matter, create a good denitrification environment for denitrification and provide an effective carbon source. The sludge age of the traditional biological denitrification system is single, which is not conducive to the colonization and cooperation of different microorganisms with large growth rates in the reactor. By combining biofilm immobilization with suspended growth, the growth of double-sludge-age microorganisms can be achieved in a single reactor, providing a theoretical basis for the research and development of efficient denitrification systems for mixed wastewater.

[0005] Based on this, the present application proposes a biological filler for strengthening denitrification in aerobic pools. By loading three layers of biological fillers, namely, an inner layer - denitrifying bacteria, a middle layer - a conductive layer, and an outer layer - nitrifying bacteria, on the filler, the problem of weak activity of denitrifying bacteria is successfully solved, and the rapid formation of a biofilm is achieved. In addition, a metal conductive layer is added in the middle to participate in the transfer of electrons during the denitrification process of microorganisms, and the biofilm layers on both sides achieve the rapid formation of a biofilm to achieve the conversion and removal of nitrogen. This method can not only maintain the biological activity of the bacteria and achieve the rapid formation of a biofilm, but also promote the separation of the bacteria and difficult-to-degrade organic matter, thereby reducing the toxic effects on the bacteria.

[0006] A method for preparing a biological filler for denitrification enhancement in an aerobic pool, comprising:

[0007] (1) placing denitrifying bacteria and a filler that has been pre-treated by washing and drying in a sodium alginate solution at the same time, which is recorded as a first immersion system, taking out the filler after being immersed for a certain period of time and then placing it in a CaCl2 solution to form a spherical gel, standing it to solidify and then washing it to obtain a filler loaded with an inner biofilm of denitrifying bacteria;

[0008] (2) dispersing the metal powder material in water to form a dispersion, dissolving sodium alginate, acrylamide and anhydrous lithium chloride in the dispersion, adding N,N'-methylenebisacrylamide and sodium persulfate, mixing thoroughly, and then adding N,N,N',N'-tetramethylenediamine, mixing thoroughly to obtain a mixed solution, soaking the filler loaded with the inner biofilm of denitrifying bacteria in the mixed solution, taking out the filler after soaking and drying it at room temperature to obtain a filler with the inner biofilm of denitrifying bacteria and the middle conductive layer in sequence on the surface;

[0009] (3) The nitrifying bacteria and the filler loaded with the inner biofilm of denitrifying bacteria and the middle conductive layer are simultaneously immersed in a sodium alginate solution, which is recorded as the second immersion system. After immersion for a certain period of time, the filler is taken out and then placed in a CaCl2 solution to form a spherical gel. After standing and solidifying, it is washed and dried at room temperature to obtain a biological filler whose surface is sequentially loaded with the inner biofilm of denitrifying bacteria, the middle conductive layer and the outer biofilm of nitrifying bacteria.

[0010] Several optional methods are also provided below, but they are not intended to be additional limitations on the above-mentioned overall solution, but are merely further supplements or preferences. Under the premise that there are no technical or logical contradictions, each optional method can be combined with the above-mentioned overall solution separately, and multiple optional methods can also be combined.

[0011] Optionally, the filler used in step (1) is a filler commonly used in aerated biological filters, including but not limited to inorganic fillers such as ceramsite, coke, and expanded aluminosilicate; and one or more organic fillers such as polyvinyl chloride, polymerized fibers, polystyrene beads, and polyurethane, preferably organic materials with good biocompatibility.

[0012] Optionally, the denitrifying bacteria are one or more of Pseudomonas, Acinetobacter, and Paracoccus; the nitrifying bacteria are one or more of Nitrosobacter, Nitrosospira, and Nitrosococcus. All of them are common species in this field and can be purchased commercially. The OD of the bacterial solution is 600 is 1-2.

[0013] The pretreatment of the denitrifying bacteria or nitrifying bacteria comprises:

[0014] The denitrifying bacteria solution or the nitrifying bacteria solution is centrifuged at a certain speed and time, resuspended with distilled water to the original scale, centrifuged again and repeated 1-2 times. Preferably, the centrifugal speed is 4000-8000 r min -1 , the centrifugation time is 5-15min.

[0015] In step (1):

[0016] Optionally, the denitrifying bacteria are expressed as 600 The denitrifying bacteria liquid with a concentration of 1-2 is obtained by centrifugation.

[0017] Optionally, in the first soaking system, the mass percentage concentration of denitrifying bacteria is 5-15%, and the mass percentage concentration of sodium alginate is 2-10%; and the soaking time is 30-60 minutes.

[0018] Optionally, the mass ratio of the filler to the denitrification is 1 to 1.5:1.

[0019] Optionally, the mass percentage concentration of the CaCl2 solution is 2%-3%; the curing time in the CaCl2 solution is 10-15 hours. The amount of the CaCl2 solution during the curing process does not need to be specifically limited, as long as all the fillers can be immersed in the CaCl2 solution.

[0020] In step (2):

[0021] Optionally, the metal powder material is a pure metal powder material or a carbon-modified metal powder material; the pure metal powder material includes but is not limited to at least one metal powder of iron, copper, manganese and nickel; the carbon-modified metal powder material includes but is not limited to a metal powder material modified by combining one of iron, copper, manganese and nickel with a carbon material. For example, the metal powder material may be an iron-carbon powder, wherein the doping content ratio of iron to carbon is 1:2.

[0022] Optionally, the amount of the metal powder material added is calculated as a mass percentage concentration of 0.4-0.8% in the mixed solution.

[0023] Optionally, the mass ratio of the three substances, sodium alginate, acrylamide and anhydrous lithium chloride, is 1-2:4-5:3-4; wherein the mass percentage concentration of sodium alginate in the mixed solution is 1%-2%.

[0024] Optionally, the mass percentage concentration of N,N'-methylenebisacrylamide in the mixed solution is 1-2%, the mass percentage concentration of ammonium persulfate in the mixed solution is 2-4%, and the mass percentage concentration of N,N,N',N'-tetramethylenediamine in the mixed solution is 2.5-5%.

[0025] Optionally, the mass ratio of the filler loaded with the inner biofilm of denitrifying bacteria to the mixed solution is 1:10-30.

[0026] Optionally, the filler loaded with the inner biofilm of denitrifying bacteria is immersed in the mixed solution for 30-60 minutes.

[0027] In step (3):

[0028] Optionally, the nitrifying bacteria are expressed by OD 600 The nitrifying bacteria liquid with a concentration of 1-2 is obtained by centrifugation.

[0029] Optionally, in the first soaking system, the mass percentage concentration of denitrifying bacteria is 5-15%, and the mass percentage concentration of sodium alginate is 2-10%; and the soaking time is 30-60 minutes.

[0030] Optionally, the mass percentage concentration of the CaCl2 solution is 2%-3%; and the solidification time in the CaCl2 solution is 10-15h.

[0031] Optionally, the mass ratio of the filler loaded with the inner biofilm of the denitrifying bacteria and the middle conductive layer to the denitrifying bacteria is 1 to 1.5:1.

[0032] Optionally, the room temperature drying: drying the filler at room temperature for 15-24 hours to obtain an active aerobic nitrification-denitrification biological filler that can be stored for a short period of time.

[0033] Optionally, in the biological filler, the thickness of the inner biofilm of denitrifying bacteria, the middle conductive layer and the outer biofilm of nitrifying bacteria are 0.5-2 mm respectively. Within this thickness range, it is not easy to fall off and does not affect electron transfer.

[0034] The present application also provides a biological filler for enhancing denitrification in an aerobic pool prepared by the preparation method. The active aerobic nitrification-denitrification biological filler needs to be stored in a low-temperature dry environment.

[0035] The present application also provides a biological filler for strengthening denitrification in an aerobic pool, comprising a basic filler and an inner biofilm of denitrifying bacteria, an intermediate conductive layer and an outer biofilm of nitrifying bacteria sequentially loaded on the basic filler.

[0036] Optionally, the basic filler is a filler commonly used in aerated biological filters, including but not limited to inorganic fillers such as ceramsite, coke, expanded aluminosilicate, and one or more organic fillers such as polyvinyl chloride, polymerized fibers, polystyrene beads, polyurethane, etc., preferably organic materials with good biocompatibility.

[0037] Optionally, the denitrifying bacteria are one or more of Pseudomonas, Acinetobacter, and Paracoccus; the nitrifying bacteria are one or more of Nitrosobacter, Nitrosospira, and Nitrosococcus. All of them are common species in this field and can be purchased commercially.

[0038] Optionally, the thicknesses of the inner biofilm of denitrifying bacteria, the middle conductive layer and the outer biofilm of nitrifying bacteria are 0.5-2 mm respectively.

[0039] The present application also provides an application of the biological filler in the denitrification enhancement of an aerobic pool, wherein the biological filler is added to the aerobic pool at 20-30% of the mass of the mud-water mixture in the biochemical aeration pool.

[0040] Compared with the prior art, the present invention has at least one of the following beneficial effects:

[0041] (1) Enhance the activity of denitrifying bacteria: By utilizing the cross-linking reaction of sodium alginate and CaCl2, denitrifying bacteria and nitrifying bacteria are fixed inside and outside the filler, respectively, maintaining the biological activity of the bacteria, achieving the rapid formation of biofilm, and reducing the toxic effects of difficult-to-degrade organic matter on the bacteria.

[0042] (2) Improve denitrification efficiency: By adding a conductive layer of metal ions in the middle layer of the filler, it can directly participate in the transfer of electrons in the microbial denitrification process, promote the conversion and removal of nitrogen, and thus improve the denitrification efficiency.

[0043] (3) Strong adaptability: It is suitable for treating industrial wastewater containing difficult-to-degrade organic matter and toxic substances, and can effectively alleviate the inhibitory effect of these substances on the denitrification process. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 This is a diagram of the packing structure of this application;

[0045] Figure 2 This is a flow chart for preparing the filler of this application.

[0046] The reference numerals shown in the figures are as follows:

[0047] 1. Basic filler; 2. Inner biofilm of denitrifying bacteria; 3. Middle conductive layer; 4. Outer biofilm of nitrifying bacteria; 5. Filler surface. DETAILED DESCRIPTION

[0048] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0049] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0050] like Figure 1As shown, a biological filler for denitrification enhancement in an aerobic pool comprises a basic filler 1 and a denitrifying bacteria inner biofilm 2, an intermediate conductive layer 3 and a nitrifying bacteria outer biofilm 4 sequentially loaded on the filler surface 5. Among them, the basic filler is a filler commonly used in aerated biological filters, including but not limited to inorganic fillers such as ceramsite, coke, expanded aluminosilicate, and one or more organic fillers such as polyvinyl chloride, polymerized fiber, polystyrene beads, and polyurethane, preferably an organic material with good biocompatibility. The thickness of the inner biofilm of denitrifying bacteria, the intermediate conductive layer, and the outer biofilm of nitrifying bacteria are 0.5-2 mm, respectively. The denitrifying bacteria are one or more of the genera Pseudomonas, Acinetobacter, and Paracoccus; the nitrifying bacteria are one or more of the genera Nitrosobacter, Nitrosospira, and Nitrosococcus. All are common strains in this field and can be purchased commercially.

[0051] like Figure 2 As shown in FIG. 1 , it is a flow chart of the method for preparing the biological filler. The preparation and application of the biological filler are described in detail with specific examples below. The raw materials used in the examples are all commercially available products and can be purchased commercially:

[0052] The strains used were purchased from the China General Microbiological Culture Collection Center, and the Pseudomonas aeruginosa strain number was CGMCC-1.10712; the nitrifying bacteria were purchased from Pro Biotech (Shanghai) Co., Ltd. Nitrifying bacteria".

[0053] Example 1

[0054] The filler used in this embodiment is ordinary polyurethane cotton filler, and the size of the polyurethane cotton is a sphere with a diameter of 4 cm and an average dry weight of 5 g.

[0055] The specific preparation method is as follows:

[0056] (1) Wash the filler with water and place it in an oven at 105°C to dry out the moisture.

[0057] (2) Pseudomonas aeruginosa (OD 600 =1) and nitrifying bacteria (OD 600 =1) respectively at 4000r min -1 Centrifuge for 10 minutes, resuspend with distilled water to the original scale, centrifuge again and repeat once to obtain Pseudomonas aeruginosa and nitrifying bacteria, respectively.

[0058] (3) Add sodium alginate into distilled water to dissolve, heat to boil and then cool.

[0059] (4) Add the Pseudomonas aeruginosa obtained by centrifugation in step (2) to the sodium alginate solution, and immerse the filler dried in step (1) in the solution.

[0060] Soak for 30 minutes, recorded as the first immersion system. In the first immersion system, the mass percentage concentration of sodium alginate is 2%, the mass percentage concentration of Pseudomonas aeruginosa is 10%, and the mass ratio of the filler to the Pseudomonas aeruginosa is 1:1.

[0061] (5) After soaking, the filler was taken out with tweezers and then put into a 2 wt% CaCl2 solution to form a spherical gel. The gel was allowed to solidify in the CaCl2 solution for 12 h and then washed with distilled water three times.

[0062] (6) dispersing iron-carbon powder (the iron-carbon powder is commercially available, and the iron-carbon doping ratio of the iron-carbon powder is 1:2) in deionized water to form a dispersion;

[0063] (7) then dissolving sodium alginate, acrylamide and anhydrous lithium chloride in the above dispersion in a mass ratio of 1:5:4 until they are completely dissolved;

[0064] (8) N,N'-methylenebisacrylamide and ammonium persulfate were added, and after vigorous stirring for 45 minutes, N,N,N',N'-tetramethylenediamine was added to obtain a mixed solution.

[0065] The amount of each raw material used in steps (6) to (8) is calculated based on its mass percentage concentration in the total amount of the mixed solution, wherein the mass percentage concentration of iron-carbon powder is 0.4%, the mass percentage concentration of sodium alginate is 1%, and the mass percentage concentrations of N,N'-methylenebisacrylamide, ammonium persulfate and N,N,N',N'-tetramethylenediamine are 1wt%, 2wt% and 4wt% respectively.

[0066] (9) The filler cleaned in step (5) is immersed in the mixed solution obtained in step (8) for 60 minutes, and then taken out and dried at room temperature to set; the mass ratio of the filler to the mixed solution is 1:20.

[0067] (10) Repeat steps (3), (4), and (5), except that Pseudomonas aeruginosa is replaced by nitrifying bacteria, and the filler is replaced by the filler dried and shaped in step (9), and the rest is the same;

[0068] (11) Dry the filler at room temperature for 24 hours to obtain Figure 1 The biological filler shown in the figure has a denitrifying bacteria inner biofilm 2, a middle conductive layer 3 and a nitrifying bacteria outer biofilm 4 loaded on the surface of the basic filler 1 in sequence;

[0069] (12) The biofiller obtained in step (1) is added to the biochemical aeration tank of a sewage treatment plant that treats refractory organic matter to remove nitrogen from the wastewater. The addition ratio is preferably 30% of the mass of the sludge-water mixture in the biochemical aeration tank. The hydraulic retention time is 12 h, the wastewater C / N is 5, the dissolved oxygen is 1 mg / L, the pH is 7, and the activated sludge concentration is 3.5 g L-1 The processing results are shown in Table 1 and Table 2.

[0070] Example 2

[0071] The filler used in this embodiment is ordinary polyurethane cotton filler, and the size of the polyurethane cotton is a sphere with a diameter of 4 cm and an average dry weight of 5 g.

[0072] The specific preparation method is as follows:

[0073] (1) Wash the filler with water and place it in an oven at 105°C to dry out the moisture.

[0074] (2) Pseudomonas aeruginosa (OD 600 =1) and nitrifying bacteria (OD 600 =1) respectively at 4000r min -1 The solution was centrifuged under the conditions of 100 ℃ and 10 min, resuspended with distilled water to the original scale, centrifuged again and repeated once to obtain Pseudomonas aeruginosa and nitrifying bacteria, respectively.

[0075] (3) Add sodium alginate into distilled water to dissolve, heat to boil and then cool.

[0076] (4) adding the Pseudomonas aeruginosa obtained by centrifugation in step (1) to the sodium alginate solution, and soaking the filler dried in step (1) in the solution for 30 minutes, which is recorded as the first soaking system. In the first soaking system, the mass percentage concentration of sodium alginate is 5%, the mass backup concentration of Pseudomonas aeruginosa is 15%, and the mass ratio of filler to Pseudomonas aeruginosa is 1:1;

[0077] (5) After soaking, the filler was taken out with tweezers and then put into a 3 wt% CaCl2 solution to form a spherical gel. The gel was allowed to solidify in the CaCl2 solution for 12 h and then washed with distilled water three times.

[0078] (6) dispersing an iron-carbon powder material (the iron-carbon powder is commercially available, and the iron-carbon doping content ratio of the iron-carbon powder is 1:2) in deionized water to form a dispersion;

[0079] (7) dissolving sodium alginate, acrylamide and anhydrous lithium chloride in the above dispersion in a mass ratio of 1:6:3 until completely dissolved;

[0080] (8) Then, N,N'-methylenebisacrylamide and ammonium persulfate were added, and after vigorous stirring for 60 min, N,N,N',N'-tetramethylenediamine was added to obtain a mixed solution.

[0081] The amount of each raw material used in steps (6) to (8) is calculated based on its mass percentage concentration in the total amount of the mixed solution, wherein the mass percentage concentration of iron-carbon powder is 0.4%, the mass percentage concentration of sodium alginate is 1%, and the mass percentage concentrations of N,N'-methylenebisacrylamide, ammonium persulfate and N,N,N',N'-tetramethylenediamine are 2wt%, 2.5wt% and 4wt%, respectively.

[0082] (9) The filler cleaned in step (5) is immersed in the mixed solution obtained in the above step (8) for 45 minutes, and then taken out and dried at room temperature to set; the mass ratio of the filler to the mixed solution is 1:20.

[0083] (10) Repeat steps (3), (4), and (5), except that Pseudomonas aeruginosa is replaced by nitrifying bacteria, and the filler is replaced by the filler dried and shaped in step (9), and the rest is the same.

[0084] (1) Dry the filler at room temperature for 20 hours to obtain Figure 1 The biological filler shown in the figure has a denitrifying bacteria inner biofilm 2, a middle conductive layer 3 and a nitrifying bacteria outer biofilm 4 loaded on the surface of the basic filler 1 in sequence;

[0085] (12) The biofiller was added to the biochemical aeration tank of a sewage treatment plant that treats refractory organic matter to remove nitrogen from the wastewater. The addition ratio was preferably 25% of the mass of the sludge-water mixture in the biochemical aeration tank, the hydraulic retention time was 12 h, the wastewater C / N was 5, the dissolved oxygen was 1 mg / L, the pH was 7, and the activated sludge concentration was 3.5 g L -1 The processing results are shown in Table 1 and Table 2.

[0086] Comparative Example 1

[0087] The difference from Example 1 is that the filler used in step (12) is a common polyurethane cotton filler without any biofilm. The rest is the same as Example 1.

[0088] Comparative Example 2

[0089] The difference from Example 1 is that the filler used is a polyurethane cotton filler that only supports denitrifying bacteria and nitrifying bacteria, and does not contain an intermediate conductive layer, that is, steps (6) to (9) are not involved in the preparation process. The rest is consistent with Example 1.

[0090] Comparative Example 3

[0091] The difference from Example 1 is that no biological filler is used.

[0092] The processing results of the above embodiments and comparative examples are shown in Table 1 and Table 2.

[0093] Table 1 Nitrogen removal of Examples 1-2 and Comparative Examples 1-3

[0094]

[0095] Table 2 Nitrogen removal rates of Examples 1-2 and Comparative Examples 1-3

[0096] Effect example TN removal rate <![CDATA[NH4 + -N removal rate]]> <![CDATA[NO3 - -N removal rate]]> COD removal rate Example 1 84％ 97％ / 92％ Example 2 77％ 98％ / 93％ Comparative Example 1 48％ 87％ / 93％ Comparative Example 2 63％ 90％ / 91％ Comparative Example 3 33％ 85％ / 92％

[0097] It can be seen from Table 1 and Table 2 that after treatment with the three-layer biological denitrification filler prepared by the present invention, the TN and NH4 + -N removal rate was significantly improved compared with the control group, among which TN removal rate could reach about 80%, NH4 + The -N removal rate can reach more than 97%, and the COD removal capacity is similar to that of the traditional activated process, and the effluent can stably reach Class A standards.

[0098] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims.

Claims

1. A method for preparing a biological filler for denitrification enhancement in an aerobic pool, characterized in that: include: (1) placing denitrifying bacteria and a filler that has been pre-treated by washing and drying in a sodium alginate solution at the same time, which is recorded as a first immersion system, taking out the filler after being immersed for a certain period of time and then placing it in a CaCl2 solution to form a spherical gel, standing it to solidify and then washing it to obtain a filler loaded with an inner biofilm of denitrifying bacteria; (2) dispersing the metal powder material in water to form a dispersion, dissolving sodium alginate, acrylamide and anhydrous lithium chloride in the dispersion, adding N,N'-methylenebisacrylamide and sodium persulfate, mixing thoroughly, and then adding N,N,N',N'-tetramethylenediamine, mixing thoroughly to obtain a mixed solution, soaking the filler loaded with the inner biofilm of denitrifying bacteria in the mixed solution, taking out the filler after soaking and drying it at room temperature to obtain a filler with the inner biofilm of denitrifying bacteria and the middle conductive layer in sequence on the surface; (3) The nitrifying bacteria and the filler loaded with the inner biofilm of denitrifying bacteria and the middle conductive layer are simultaneously immersed in a sodium alginate solution, which is recorded as the second immersion system. After immersion for a certain period of time, the filler is taken out and then placed in a CaCl2 solution to form a spherical gel. After standing and solidifying, it is washed and dried at room temperature to obtain a biological filler whose surface is sequentially loaded with the inner biofilm of denitrifying bacteria, the middle conductive layer and the outer biofilm of nitrifying bacteria.

2. The preparation method according to claim 1, characterized in that: Step (1): The denitrifying bacteria were OD 600 The denitrifying bacteria liquid with a concentration of 1-2 is obtained by centrifugation; In the first soaking system, the mass percentage concentration of denitrifying bacteria is 5-15%, and the mass percentage concentration of sodium alginate is 2-10%; the soaking time is 30-60 minutes; The mass percentage concentration of the CaCl2 solution is 2%-3%; the solidification time in the CaCl2 solution is 10-15h; The mass ratio of the filler to the denitrifying bacteria is 1-1.5:

1.

3. The preparation method according to claim 1, characterized in that: In step (2): the metal powder material is a pure metal powder material or a carbon-modified metal powder material; the pure metal powder material is at least one metal powder of iron, copper, manganese and nickel; the carbon-modified metal powder material is a metal powder material modified by combining one of iron, copper, manganese and nickel with a carbon material.

4. The preparation method according to claim 1, characterized in that: In step (2): The amount of the metal powder material added is calculated as a mass percentage concentration of 0.4-0.8% in the mixed solution; The mass ratio of the three substances of sodium alginate, acrylamide and anhydrous lithium chloride is 1-2:4-5:3-4; wherein the mass percentage concentration of sodium alginate in the mixed solution is 1%-2%; The mass percentage concentration of N,N'-methylenebisacrylamide in the mixed solution is 1-2%, the mass percentage concentration of ammonium persulfate in the mixed solution is 2-4%, and the mass percentage concentration of N,N,N',N'-tetramethylenediamine in the mixed solution is 2.5-5%; The mass ratio of the filler loaded with the inner biofilm of denitrifying bacteria to the mixed solution is 1:10-30; The filler loaded with the inner biofilm of denitrifying bacteria is immersed in the mixed solution for 30-60 minutes.

5. The preparation method according to claim 1, characterized in that: In step (3): The nitrifying bacteria were expressed by OD 600 The nitrifying bacteria solution with a concentration of 1-2 is obtained by centrifugation; In the first soaking system, the mass percentage concentration of denitrifying bacteria is 5-15%, and the mass percentage concentration of sodium alginate is 2-10%; the soaking time is 30-60 minutes; The mass percentage concentration of the CaCl2 solution is 2%-3%; the solidification time in the CaCl2 solution is 10-15h; The mass ratio of the filler loaded with the inner biofilm of the denitrifying bacteria and the middle conductive layer to the denitrifying bacteria is 1-1.5:

1.

6. The preparation method according to claim 1, characterized in that: In the biological filler, the thicknesses of the inner biofilm of denitrifying bacteria, the middle conductive layer and the outer biofilm of nitrifying bacteria are 0.5-2 mm respectively.

7. A biological filler prepared by the preparation method according to any one of claims 1 to 6.

8. A biological filler for enhancing denitrification in an aerobic pool, characterized in that: The invention comprises a basic filler and a denitrifying bacteria inner biofilm, a middle conductive layer and a nitrifying bacteria outer biofilm which are sequentially loaded on the basic filler.

9. The biological filler according to claim 8, characterized in that The thicknesses of the inner biofilm of denitrifying bacteria, the middle conductive layer and the outer biofilm of nitrifying bacteria are 0.5-2 mm respectively.

10. The use of the biological filler according to any one of claims 7 to 9 in strengthening denitrification in an aerobic pool, characterized in that: The biological filler is added into the aerobic tank at 20-30% of the mass of the mud-water mixture in the biochemical aeration tank.

Images